Pump plunger



n Q June 18, 1929. J.-H. JEFFRlEs E-r AL.

PUMP PLUNGER Fild June fr, 192e 1 @imn i nlp;

John H. Jeffries A Edward M4Dozerlfl/ l M aotnuj .lune '18, 1929.

unirse sTA'rEs PATENT OFFICE.

JOHN H. JEFFBIES ANI) EDWARD M. DOHERTY, F LOS ANGELES, CALIFORNIA.' i

PUMP PLUNGER.

Application led June 7, 1926. Serial No. 114,054.

This `invention relates to pump plungers, and more especially to that type ot' plunger having a'cup of flexible material adapted to engage the inner face of the pump cylinder in order to prevent leakage between the plunger-and said cylinder.

In pumps heretofore constructed and provided with plunger cups7 the construction of vthe plunger is such that the pressure of the fluid being pumped, upon inward stroke of the plunger, forces the flexible cup between the plunger and the c flinder, thus causing the cup to buckle, an( the buckling causes the rim of the cup to be contracted. 0bviously, contraction of the rim permits sand and other foreign substances to deposit between the cup and cylinder wall, producing excessive wear on the cylinder and cup.

An object of this invention is to avoid the foregoing difculty and to insure relatively long liie of the cup.

J-tnother object of this invention is to provide a construction that will support the cup in. such manner that it cannot be forced between the plunger and wall of the cylinder.

Other objects and advantages will appear in the subjoined detailed description.

The accompanying drawings illustrate the invention.

Figure 1 is a sectional view of a plunger constructed in accordance with the provisions ot' this invention, a cylinder being indicated in broken lines.

Figure 2 is a cross section of the plunger on the line indicated by 2 2, Figure 1.

Figure 3, is a view looking at the lower end of Figure 1.

The plunger body may be of any suitable construction and, in this instance, the construction is as follows: There is provided a tubular stem t having thereon an enlarged portion 5, which is provided with an internal shoulder t3 seating against an internal shoul der 7 on the stem 4. The shoulders 6, 7 are held in engagement by a tubular nut 8 that is threaded in one end of the member 5, against one end of the stem 4. A sleeve 9 lits tightly upon the stem 4f, and mounted to'shift on said sleeve is a valve 10 adapted to engage a recessed seat 11 in one end of the member 5. lthe construction of the valve 10 and the resil- :ient means for urging said valve toward its seat need not be described in detail herein as the same have been fully described in our 55 Patent No. 1,491,044, dated April 22, 1924:.

Tim member 5 is provided With a DOI'tiOD 12 of reduced outside diameter terminated at one end by an external shoulder 13 on the member 5. The portion 12 is provided at its other end with a cup seat 14, screw threaded onto said portion 12, and betweenthe shoul- V ter portion 12 extends. When a' plurality of seats 15 is employed, it is necessary to provide other cup seats 17, each of which has a portion 18 of reduced outside diameter extending inside of the adjacent cup 15 and an enlarged Aportion 19 forming a seat for one of the cups The member 14 and the enlargements 19 are `provided with recesses 20, the outer wall portions o which have their inner faces curved outwardly and upwardly, as indicated at 21 and the rim of each recess 20 extends at least to the level of the lower end of the member 18 that engages the cup 15 fitting in saidrecess. It is even` preferable to extend the rim of the recess somewhat above the level of the lower end of the adjacent member 18. The recess 20 is greater in depth than the thickness of the cup and as shown in the drawings the mouth of this recess is of substantially less diameter than the outside dia-meter of the cup seat, the wall of the recess adjacent to the mouth thereof being normal to the horizontal plane in which the upper extremity of said seat lies. By this construction,iiiid pressure against the lower portion of the inside of the packing cups cannot force the cups between the plungerand the cylinder wall indicated at A. When the cup holding recesses are shallow, as ordinarily constructed, or, in other words, constructed so that the recess rims are below the level of the lower end of the spacing member, the material oi? which the cup is made is bent by the fluid pressure and crowded between the plunger and cylinder wall, thus producing buckling of the cylindrical wall ofthe packing cup and the buckling results in contraction of the rimof the cup away from the cylinder wall, thus permitting sand to enter between the packing cup and cylinder wall, resulting in scoring of the cylinder within a short period of time after the plunger starts to operate.

The construction just described may be further described as follows: The depth of each recess 20 is as great as the thickness of the cup 15 and, in the instance shown, the depthofeach recess is considerably greater than the thickness of the cup. When the cup containing recesses are constructed as described, the fluid pressure within the lower portions of the cups cannot force the lower portions of the cups between the cup supporting members 14 or 17,

as the case may be, because said cupsarehacked externally by metal to a point abovey is applied herein to each of said members and said term will be employed in the appended claims.

It will be seen that the uppermost cup 15 is held between the shoulder 13 and the adjacent member 17 and that the lower ends of the members 17 constitute shoulders 22 between which and the next lower seat, the cup 15 is clamped.

The invention operates as follows: When the plunger moves on its down stroke, the fluid being pumped presses against the under face of the valve 10, causing said valve to open so that the fluid will pass into the space above the plunger. Upon reversal of the plunger, the

. fluid pressure above the valve 10 will hold said valve closed and fluid pressure within the cups 15 will hold the rims of said cups in close contact with the cylinder, thus avoiding leakage of fluid above the plunger past the cups to the space beneath the plunger where a partial vacuum is tended to be produced upon the up stroke of the plunger. On the down stroke of the plunger, the projecting portion of the cup will be relieved from t-he pressure bending to pre-ss it against the working barrel and will he free from contact therewith, due to the contol body provided with an annular shoulder, a

cup seat surrounding the body and provided with a recess, the outer wall of the recess being curved outwardly and upwardly, and a flexible packing cup fitting the recess and shoulder, the depth of the recess being greater than the thickness of the cup, the wall of the recess adjacent to the mouth thereof being normal to the horizontal plane in which the upper extremity of said seat lies, and the mouth of the recess being of substantially less diameter than the outside diameter of the cup seat;

Signed at Los Angeles, California, this 21st day of May, 1926.

EDWARD M. DOHERTY. Signed at Santa Barbara, California, by JOHN H. JEFFRIES, this 25 day of May, 1926.

JOHN H. JEFFRIES. 

